A camera having a zooming capability is able to acquire zoomed in and zoomed out images. Upon zooming in, the camera is directed so that it is centered on the object to be zoomed in and hopefully, upon zooming in, the object to be zoomed in is displayed zoomed in, in the zoomed in camera view.
U.S. Pat. No. 4,527,201 relates to a zoom indicating apparatus for a video zoom camera that provides a viewfinder raster display of a scene within the field of view of the camera superimposes upon the raster display a zoom frame that indicates the portion of the scene that would be within the field of view of the camera at its maximum zoom setting. The apparatus converts a zoom setting signal from the camera to a signal corresponding to the magnification at that zoom setting, employs the magnification signal for generating zoom frame signals which define the size and location of the zoom frame on the display, and combines the zoom frame signals with the video signal from the camera to form a composite video signal that is applied to the display. The apparatus automatically adjusts the position of the zoom frame on the display so as to compensate for misalignment between the optical axis of the camera lens and the center of the scanned image on the camera sensor tubes.
US 2009/0102920 relates to an optical apparatus that includes a zoom lens unit, a pan/tilt unit configured to at least one of pan the zoom lens unit and tilt the zoom lens unit, and a center-shift information storage portion configured to store a shift amount of an optical axis for every zooming position, and has a mechanism configured to correct a shift of the optical axis caused by zooming, by driving the pan/tilt unit by the shift amount of the optical axis stored in the center-shift information storage portion.
Unfortunately, cameras having high zooming capability can be associated with problems when zooming in. Due to mechanical deviations in the camera, the object to be zoomed in, i.e. the object centered in a zoomed out view, may not even be visible in the zoomed in view. This is illustrated by an example in FIGS. 1a and b each comprising a camera view. FIG. 1a displays a zoomed out camera view comprising two houses 10 and 20. The camera is centered on house 10, more specifically on the circular window arranged in the roof. Upon zooming in, however, due to mechanical deviations in the camera, the zoomed in view does not display the circular window and not even the house 10. Instead, the zoomed in view, illustrated by FIG. 1b, displays the house 20. One way to solve this problem would be to zoom in the camera, redirect it towards the circular window and then zoom the camera out again. This is however time-consuming. It is particularly time-consuming for surveillance cameras that are not panned nor tilted during use after installation.
Thus, it is apparent that surveillance cameras having high zooming capability are associated with problems.